1. Field of the Invention
This invention relates to a masking device which determines the area of printing on a photosensitive medium while being interposed between a photographic printing light source and the photosensitive medium.
2. Related Art
In a photographic printing apparatus, an image on the negative film is printed on a photosensitive medium such as prints: a framed (with-border) print having a frame portion where no printing is effected, and a non-framed (borderless) print formed by printing the original image over the entire area of the print. It is therefore necessary to change masks that are adapted for these two types of print. It is therefore necessary to change masks that are adapted for these two types of print.
To cope with this problem, the inventor of the present invention has proposed, in U.S. patent application Ser. No. 123,455 filed on Nov. 20, 1987, now U.S. Pat. No. 4,806,983, issued Feb. 21, 1989 a masking device for use in a photographic printing apparatus free from need for changing masks for printing of non-framed and framed images.
In this device, a pair of moving bases are moved in the widthwise direction of a photosensitive medium in accordance with the size thereof, and auxiliary mask members supported on the moving bases are thereafter made to advance or retreat depending on whether the image is printed with a frame or without frame. That is, the area of printing of a non-framed or framed image is defined in the widthwise direction by the auxiliary mask members alone.
It is therefore necessary for this device to accurately move the auxiliary mask members to two positions: non-framed image printing position; and framed image printing position.